I'm sure I'll get some flak for this, and I don't know if it will be an option for you, but...
Do you have a friend who has a chain link dog pen in a rural area? Tumnus' problem wasn't as severe as your dog's, but he would whine, etc. while in his crate. If I left him out, he would bark and howl until sunset - not to mention shred my pillows. My relatives have a dog lot - 6 ft chain link fence surrounding an 8'x 8' area (no hazards) - and they live in a very rural area. Everyone's dog barks there, so Tumnus was able to yowl all he wanted, and he quickly found out that making all of that racket didn't get him out of there any quicker. In fact, the more noise he made, the longer he had to stay confined. I waited until he quieted down, and then I approached to dog lot and waited for Tumnus to lay down. He was never allowed out until he (1) lay down and (2) was quiet (while laying down) for at least 2 minutes. This worked wonders with him when I came back to my apartment. Again - let me say that Tumnus wasn't a severe SA case. He wears his basket muzzle while in his crate because he will gnaw on the bars and any nearby items (pillows, etc.). I never thought it would be possible for him to go into his crate without being pushed, but today I only had to lead him to the crate to get him to go in. Many times he will remain laying down until he knows I'm going to let him out, but I use the same methods I did with the dog lot - he has to be quiet and calm (laying down) for at least 2 minutes before he gets to come out.
I'm sorry for such a long-winded answer, but I hope this helps you. Good luck!
Totally old school thinking and very, very inappropriate.